The invention relates to a method of processing nitrile polymers into articles. The polymer can be processed into various forms such as densified pellets (lens), or the final article of manufacture such as film sheets, pipe, bottles, or injection molded or blow molded articles.
Typically, the coagulated latex formed by a polymer reaction must be processed prior to its end use. This processing may consist of densification of the polymer strands into pellets, compounding or mixing the resin with various additives to improve certain physical properties, extrusion to pellet or final article, and injection blow molding.
Common to these processing steps is the heating of the polymer to a plastic state. It has been discovered that improved yellowness index and impact strength can be obtained by displacing oxygen with an inert gas during the heating and plasticizing step.